class CodeVerify {
	constructor(el) {
		this.el = el
	};
	code_verify(show_num) {
		var canvas_width = $('#'+ this.el).width();
		var canvas_height = $('#' + this.el).height();
		var canvas = document.getElementById(this.el); //获取到canvas的对象，演员
		var context = canvas.getContext("2d"); //获取到canvas画图的环境，演员表演的舞台
		canvas.width = canvas_width;
		canvas.height = canvas_height;
		var sCode = "A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
		var aCode = sCode.split(",");
		var aLength = aCode.length; //获取到数组的长度
	
		for (var i = 0; i <= 3; i++) {
			var j = Math.floor(Math.random() * aLength); //获取到随机的索引值
			var deg = Math.random() * 30 * Math.PI / 180; //产生0~30之间的随机弧度
			var txt = aCode[j]; //得到随机的一个内容
			show_num[i] = txt.toLowerCase();
			var x = 10 + i * 20; //文字在canvas上的x坐标
			var y = 20 + Math.random() * 8; //文字在canvas上的y坐标
			context.font = "bold 23px 微软雅黑";
	
			context.translate(x, y);
			context.rotate(deg);
	
			context.fillStyle = this.randomColor();
			context.fillText(txt, 0, 0);
	
			context.rotate(-deg);
			context.translate(-x, -y);
		}
		for (var i = 0; i <= 5; i++) { //验证码上显示线条
			context.strokeStyle = this.randomColor();
			context.beginPath();
			context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
			context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
			context.stroke();
		}
		for (var i = 0; i <= 30; i++) { //验证码上显示小点
			context.strokeStyle = this.randomColor();
			context.beginPath();
			var x = Math.random() * canvas_width;
			var y = Math.random() * canvas_height;
			context.moveTo(x, y);
			context.lineTo(x + 1, y + 1);
			context.stroke();
		}
	};
	randomColor() { //得到随机的颜色值
		var r = Math.floor(Math.random() * 256);
		var g = Math.floor(Math.random() * 256);
		var b = Math.floor(Math.random() * 256);
		return "rgb(" + r + "," + g + "," + b + ")";
	}
}
